Meeting Abstract
23.5 Monday, Jan. 4 Productive Procrastination: Stable Isotopes Reveal Benefits Associated with a Reproductive Delay in Flesh Flies WESSELS, F. J.*; HAHN, D. A.; University of Florida; University of Florida fwessels@ufl.edu
The timing and magnitude of reproductive resource allocation are not static, they are flexible and highly tuned to external conditions. However, a critical question is whether this plasticity is adaptive, allowing organisms to maximize fitness when exposed to variable environmental conditions. Before they can reproduce, most insects must reach a minimal nutritional threshold. Previous research has shown that the flesh fly, Sarcophaga crassipalpis, can reach the minimum nutritional reproductive threshold after a single protein meal. However, if flesh flies are provided with low quality resources, they will delay reproduction compared to individuals receiving high quality resources. This plastic delay may be adaptive if it provides female flies with more time to obtain additional high quality meals and enhances reproduction. To test if this reproductive delay is consistent with adaptive plasticity, we provided three sequential resource pulses early, middle, and late during the reproductive delay period. As expected, poorly fed flies delayed reproduction and flies that received a resource pulse during the delay period benefited from the additional nutrients. Flies that received a resource pulse earlier in the delay period had greater reproductive output and provisioned their eggs faster than flies that received a later pulse. In addition, by using diets with distinct 13C stable isotope profiles we found that flies receiving the earlier pulse were able to incorporate more dietary carbon into their eggs and somatic tissue than those provided a later pulse. These results suggest that the reproductive delay in S. crassipalpis is consistent with adaptive post-threshold plasticity.
